Circuit breaker mechanism mounting plate assembly



Nov. 4, 1969 c. E. GRYCTKO 3,477,044

CIRCUIT BREAKER MECHANISM MOUNTING PLATE ASSEMBLY Filed April 19, 1967 5 Sheets-Sheet l INVENTOR. 6'41?! 5. GRYC'T/Yd Nov. 4, 1969 c. E. GRYCTKO 3,477,044

CIRCUIT BREAKER MECHANISM MOUNTING PLATE ASSEMBLY Filed April 19, 1967 3 Sheets-Sheet 2 BY a r/ 01mm, Fade-e, Giza fab-Fm Nov. 4, 1969 c. E. GRYCTKO CIRCUIT BREAKER MECHANISM MC UNTING PLATE ASSEMBLY 3 Sheets-Shae:v 3

Filed April 19, 1967 United States Patent 3,477,044 CIRCUIT BREAKER MECHANISM MOUNTING PLATE ASSEMBLY Carl E. Gryctko, Haddon Heights, N.J., assignor, by mesne assignments, to I-T-E Imperial Corporation, Philadelphia, Pa., a corporation of Delaware Filed Apr. 19, 1967, Ser. No. 632,045 Int. Cl. H01h 9/00, 13/02 US. Cl. 335--23 Claims ABSTRACT OF THE DISCLOSURE This invention relates to electric circuit breaker component mounting means and more particularly to a separable circuit breaker mechanism mounting plate assembly disposed within a circuit breaker casing.

In recent years there has been considerable effort expended in the electrical industry to reduce the size of circuit protective equipment. For example, in the area of small air circuit breakers of the type with which the instant invention is intended to cooperate, the industry has seen acceptance of one-half inch wide circuit breakers as a substitute for the long accepted one inch wide breaker. Further evidence of the present emphasis on reduction in size and simplicity in design is evidenced by United States patent application Ser. No. 587,709, now Patent No. 3,347,574 filed Oct. 19, 1966, entitled Circuit Breaker Resetting and Closing Mechanism, and assigned to the assignee of the instant invention, where there has been described in great detail a novel circuit breaker which has achieved utmost simplicity in design and maximum reduction in overall size.

Simultaneously with the development of smaller and more simplified circuit breakers, and related thereto, engineers have re-examined the operating characteristics of small circuit breakers and looked for ways in which the manufacture thereof might be simplified. They have also sought ways to make these circuit breakers more durable.

Circuit breakers of the prior art generally have a casing comprised of a moldable plastic material, which has its internal walls so molded as to provide upraised lugs and tabs and to provide indentations and apertures for receiving and mounting various discrete elements comprising a circuit breaker. This complicates the housing molding operation by requiring unnecessary critical dimensional tolerances in the completed molded structure. Furthermore, these mounting elements, being made of plastic, may wear out more rapidly than desired and are not as strong and durable as metallic mounting elements would be.

To overcome these difficulties, the present invention contemplates providing a circuit breaker with a common, relatively flat (vis-a-vis the breaker casing) mounting plate upon which nearly all movable components of the operating mechanism of the circuit breaker may be directly secured and to which the remainder of the movable components of the circuit breaker mechanism may be indirectly secured. The plate is provided with various apertures and upraised tabs to which the components ice of the circuit breaker mechanism are mounted and which, as needed, serve as points or surfaces about which various components of the circuit breaker mechanism may pivot.

For illustrative purposes, the movable breaker components may comprise a movable contact, a breaker trip mechanism to separate the movable contact from a stationary one, a circuit reclosing or relatching mechanism to reclose the tripped open contacts, and a handle for manually opening and closing the breaker contacts.

The circuit breaker mechanism mounting plate assembly, being itself thin, helps minimize the width of a circuit breaker in which it is employed. Being separate from the breaker casing, the mounting plate assembly with its tabs and apertures, need not be formed of the same material as the molded breaker casing. Thus, it can be formed of a more durable material, such as steel, whereby the rubbing between the movable components and the mounting plate assembly will not readily wear down the mounting plate assembly tabs and pivot surfaces. Further, the mounting plate assembly can be readily formed by cutting or stamping. If the breaker casing itself contains the mounting means for the movable breaker components, the casing must be molded to critical tolerances, which is more difficult than cutting or stamping a flat plate comprised of metal. In addition, the breaker components can be mounted to the mounting plate assembly before that assembly is positioned in the breaker casing, whereby the assembler of the breaker components need not operate within the confined space of the breaker casing.

Accordingly, it is an object of the present invention to provide a circuit breaker mechanism mounting plate assembly adapted to minimize the width of a circuit breaker.

It is another object of the present invention to provide a circuit breaker mechanism mounting plate assembly which is formed separately from and can be inserted into a preformed circuit breaker casing.

It is another object of the present invention to provide a circuit breaker mechanism mounting plate assembly including means for receiving and mounting the components of a circuit breaker.

It is a further object of the present invention to provide a circuit breaker mechanism mounting plate assembly upon which the movable circuit breaker components can be either directly or indirectly mounted prior to the insertion of the mounting plate assembly into the preformed circuit breaker casing.

Other objects and a fuller understanding of the instant invention may be had by referring to the following description and drawings, in which:

FIGURE 1 is an exploded perspective view of the internal components of a circuit breaker constructed in accordance with the teachings of the instant invention, and including the circuit breaker mechanism mounting plate assembly of the instant invention;

FIGURE 2 is a plan view, with the cover removed, of the circuit breaker of FIGURE 1, with the operating mechanism thereof in the on position;

FIGURE 2A is a section along the line and in the direction 2A2A of FIGURE 2 and illustrates the mounting for the mounting plate assembly of the instant invention;

FIGURE 2B is a section along the line and in the direction 2B-2B of FIGURE 2 and illustrates the mount ing for the circuit breaker stab terminals;

FIGURE 3 is a partial view of the circuit breaker of FIGURE 2, with the parts thereof in the off position; and

FIGURE 4 is a view similar to FIGURE 3, but showing the circuit breaker in the tripped position.

Referring to FIGURE 1, there is shown the internal mechanism of a circuit breaker constructed in accordance with the principles of the instant invention. It is reemphasized that although the circuit breaker mechanism mounting plate assembly 14 of the instant invention will be specifically described with respect to the internal mechanism 10 shown in application Serial No. 587,709, now Patent No. 3,377,574, it is to be understood that such disclosure is intended in no way to limit the application of the instant invention, since the instant invention is equally applicable to any circuit breaker mechanism.

Similarly, it is to be understood that although the instant invention will be described with respect to a circuit breaker for the protection of a single phase of current, the instant invention can be readily employed in a multi-phase circuit breaker, e.g. by using a plate assembly in every phase of a multi-phase circuit breaker.

The circuit breaker mechanism 10 includes the common plate 14 of the instant invention, which is integrally provided with the following parts: an upstanding cradlepivoting tab 16; an upstanding relatching-pivoting tab 18; an upstanding tripper mechanism-pivoting tab 20; and an upstanding spring-retaining tab 22. In addition the plate 14 includes an elongated slot 24; a generally centrally located operating handle-pivoting aperture 26; and an arcuate slot 28 which receives an upstanding tab portion of the operating handle 30, as hereinafter described. The combination of the common plate 14 and the aforementioned tabs, apertures and slots comprises the mounting plate assembly of the instant invention.

To carry out the objects of the present invention, the mounting plate 14 is preferably very thin and flat as compared with the width of the latter described circuit breaker casing 110, with the exception of the upstanding tabs. The material of which the common mounting plate 14 is comprised is not critical to the instant invention and may be any substance which can be formed or molded as required by this invention, e.g. any plastic material and any metal. However, since the operating or moving parts of the circuit breaker are mounted to the common plate 14, the plate 14 is preferably comprised of a material, such as steel, which will not be worn by the repeated relative movements of the circuit breaker components with respect to the mounting plate 14. Furthermore, if a metal such as steel is employed, the mounting plate can be manufactured by first cutting or punching an appropriate pattern from a flat sheet of metal. Then, apertures in appropriate places can be cut out; and upstanding tabs can be formed merely by cutting the plate in proper places and then bending to an upstanding condition all of the necessary tabs. Alternatively, an entire mounting plate assembly could be simply formed by stamping a sheet of metal in an appropriately shaped die.

The common mounting plate of the instant invention can be readily manufactured separately from a casing for the circuit breaker in which the plate is to be employed. As desired, all movable components of the circuit breaker can be mounted to the mounting plate before it is placed within the circuit breaker casing, thereby making the assembly of circuit breaker components easier. A circuit breaker with which the mounting plate assembly of the instant invention can be employed is now described.

The operating handle 30 of the circuit breaker includes an upstanding knob receiving tab 32 at one end thereof, and a pair of upstanding tabs 34 and 36 at the opposite end thereof. Tab 34 is provided with an open-ended slot 38 which fits over a portion 40 of the mounting plate defining the aperture 26 whereby the operating handle 30 may experience rotation in a plane parallel to the plane of the mounting plate 14 about the point 40. The second tab 36 of the operating handle 30 is freely received within the arcuate slot 28 and extends forward of the mounting plate 14 when the operating handle 30 is placed behind the mounting plate 14 with the openended slot 38 riding on the point 40. The handle 30 is thus directly mounted to the plate 14. Biasing means in the form of spring 42 is secured at one end thereof to the tab 36 and at the opposite end thereof to the upstanding spring-retaining tab 22 so as to constantly bias the operating handle 30 in a counterclockwise direction in FIG- URE 1 about the pivot defined by the slot 38 and point 40.

A cradle 44 includes a bifurcated end 46, the two arms 48 and 50 of which include aligned apertures 52 which receive the cradle pivoting tab 16 of the mounting plate 14. The cradle 44 is thus also directly mounted to the plate 14. The opposite end of the cradle 44 includes an upstanding latch tip 54 which cooperates with the latch 56 of the tripping mechanism 80, as will be described in further detail. Intermediate the ends of the cradle 44 is an overturned tab 58 which cooperates with an openended slot 60 provided at one end of a movable contact arm 62 to permit rotation of the movable contact arm 62 about point 64 on the cradle 44 when the movable contact arm 62 is inserted up and under the over-tamed tab 58. Being mounted to the cradle 44, the movable contact arm is indirectly mounted to the plate 14. Cradle 44 has a kicker projection 44a which aids in separating the breaker contacts in the event the breaker is tripped, as is described below.

The opposite end of the movable contact arm 62 integrally carries a generally S-shaped spring-retaining portion 66 and also carries a generally L-shaped portion 68 which carries the movable contact pad 70 thereon. Disposed opposite to the movable contact pad 70 is a stationary contact pad 76 secured to the stationary stab terminal 78 of the breaker. The contact pads 70 and 76 comprise the cooperating contacts in the breaker.

A main operating spring 72 is secured at one end thereof to the S-shaped spring-retaining portion 66 and at the opposite end thereof to a spring-retaining portion 74 which is an integral portion of the upstanding knobretaining portion 32 of the operating handle 30.

The tripping mechanism generally designated at 80 includes a bimetallic element 82 and a magnetic element 84 to which is secured the latch 56. As explained in greater detail below and in copending patent application Ser. No. 692,561 filed Dec. 21, 1967, in the name of F. Myers and W. Goodnow, entitled Circuit Breaker Thermal and Magnetic Tripping Mechanism, which is assigned to the assignce of the instant invention, in response to predetermined overload or instantaneous fault conditions, tripper mechanism will rotate clockwise in FIGURE 1 to move the latch 56 out of engagement with the latch tip 54 of cradle 44 to permit cradle 44 to rotate clockwise causing kicker projection 44a to strike movable contact support arm 62 causing it to rotate clockwise and separating movable contact 70 from stationary contact 76-. The blow drives arm 62 to rotate over center part pivot 64 and the main operating spring 72 causes further clockwise rotationof contract arm 62 until arm 62 strikes tip 54 of cradle 44 which halts the arm 62. Hence, tripping mechanism 80 interrupts current fiow through the path defined by stab 78, stationary contact pad 76, movable contact pad 70, conductive braid 86, bimetallic element 82, conductive braid 88, and stab 90. The tripping mechanism has an aperture 89 through which is passed mounting plate tab 20, about which tab tripping mechanism 80 pivots. Thus the tripping mechanism is directly mounted to plate 14. The tripping mechanism is part of a circuit interruption mechanism, the other part of which is handle 30. Either handle 30, as will be discussed below, or mechanism 80 can be used to separate movable contact 70 from stationary contact 76.

The automatic relatching means 12 employed in conjunction with the mounting plate assembly of the instant invention is more fully set out in copending patent application Ser. No. 587,709, now Patent No. 3,377,574, which is assigned to the assignee of the instant invention, and includes first and second members 92 and 94, respectively, which are joined as by a pin 96 for rotation relative to one another. The first member 92 includes a centrally located aperture 98 which is received and carried by the upstanding pivot point 18 on mounting plate 14 to permit rotation of the linkage assembly relative to the plate 14. Hence, automatic relatching means 12 is directly mounted to plate 14. The first member 92 also includes a pair of actuating surfaces 100 and 102, for purposes to be further explained, while the second member 94 terminates in an upstanding actuating surface 104 which itself terminates in a rearwardly disposed portion 106 which lies in a plane behind the planar surface of the second member 94 so that it may ride behind the mounting plate 14 with the upstanding actuating surface 104 projecting through the elongated slot 24 and beyond the front surface of the plate 14. It may be noted that actuating surface 102 of member 92 retains one end of a biasing spring 103, the opposite end of which is secured to a hook-like projection 105 provided on the tripping mechanism 80 to constantly bias the first member 92 of the automatic relatching mechanism in a counterclockwise direction about the pivot point 18. Relatching means 12 is part of a circuit reclosing mechanism, the other part of which is handle 30. Either handle 30, as will be discussed below, or means 12 can be used to re-engage movable contact 70 and stationary contact 76.

The various circuit breaker components, including the relatch mechanism 12, the cradle 44, the movable contact arm 60, and the operating handle 30 and all upstanding tabs on these components, are made as thin as possible, in comparison with the width of the breaker casing, in order to minimize the width of the completed circuit breaker. To accomplish this aim, these various circuit breaker components can, in the same manner as the mounting plate assembly, be formed from a single sheet of material, such as steel.

All of the movable circuit breaker components may be mounted to the plate 14 before it is mounted in the belowdescribed casing 110. At the option of the assembler, various components may be mounted after the plate 14 has been mounted in the casing 110.

While the circuit breaker components are herein shown mounted by means of tabs and apertures, any component might be mounted with any other securing means, such as screws, pins or rivets.

Referring to FIGURE 2, there is shown the manner in which the circuit breaker operating mechanism cooperates within a circuit breaker casing generally indicated at 110. The casing 110 normally includes a cover, not shown, which when removed reveals the mechanism housing cavity 112. The casing walls include appropriately located passageways 113 for stabs 78 and 90; a passageway 114 to permit the exit of gases generated during circuit interruption in the manner taught by United States patent application Serial No. 565,500 filed July 29, 1966, in the name of Carl E. Gryctko, and assigned to the assignee of the instant invention; and a passageway 115 provided through the outer casing wall'to house an adjusting screw 117 which is screw-threaded through an upstanding tab 119 provided on the mounting plate 14 to vary the position of the bimetallic element 82 and hence the entire tripping mechanism 80 relative to the latch tip 54 of cradle 44. (Note that the tripping assembly 80 is constantly biased in a counterclockwise direction in FIGURE 2 by the biasing spring 103 secured between the hook-like projection 105 on the tripping mechanism and the actuating surface 102 provided on the first member 92 of the automatic relatching mechanism.) The external casing wall is also removed at 116 through which an operating knob 118 may be secured to the operating handle 30 of the internal mechanism in a manner to be further described. The upper arcuate opening 116 is defined at opposite ends thereof by casing wall projections 120 and 122.

The stab terminals 78 and 90 are positioned within the above noted casing passageways 113. Passageways 113 have depressions 113a into which are fitted bosses 78a and a to retain the stab terminals 78 and 90 in stationary condition (see FIGURE 2B). The only circuit breaker components that are not either directly or indirectly mounted to the mounting plate assembly 14 are the stab terminal 78 which bears the stationary contact 76 and the stab terminal 90. These components remain stationary during circuit breaker operation.

In the interior cavity 112 and upstanding from the rear wall 124 of the casing there is provided an internal generally U-shaped projection 126 which houses the bifurcated end 46 of the cradle 44 which in turn is pivoted upon the tab 16 of the mounting plate 14.

The mounting plate 14 has apertures 131 for receiving positioning means for said plate. Molded to the casing wall are lugs 132 (see FIGURE 1) which are positioned to register with and pass through apertures 131 (see FIGURE 2A) to retain plate 14 in position within casing 110. Alternatively, other securing means, e.g. screws and rivets, might be used to position plate 14. The circuit breaker casing need contain no other projections, tabs, or apertures for mounting the circuit breaker components since the mounting plate assembly contains mounting means for all of the movable breaker components. Thus, manufacture of circuit breaker casings is made easier and the casing need not be formed or otherwise firmed to critical tolerances to be able to position all breaker components as is required in other circuit breakers.

The operating knob 118 of the circuit breaker is actual- 1y an integral portion of a one-piece arc-like member 124a which is guided for movement within the interior 112 of the casing 110 by the internal surfaces of the casing walls as well as by the upstanding projection 126. The arc-like member 124a has a cutout notch 127 which receives the upstanding tab 32 of the operating handle 30 whereby rotation of the knob 118 between limits defined by wall projections 120 and 122 will similarly rotate the operating handle 30. After all components have been assembled in the base portion of the circuit breaker casing, the cover (not shown) of the circuit breaker casing is positioned over the base portion and it is secured thereto by a conventional securing means. Thus, there has been described a circuit breaker mechanism mounting plate assembly adapted for receiving and mounting a circuit breaker operating mechanism and designed to reduce the size and width of the circuit breaker, to simplify the manufacture thereof and to make the elements mounting the circuit breaker components sturdier and more resistant to wear through use.

The operation of the circuit breaker will now be described. In FIGURE 2 the circuit breaker is in the on position, that is, with the contact pads 70 and 76 completing a circuit path through the stab 78, contact pads 70, 76, the conductive braid 86, the bimetallic element 82, the conductive braid 88 and through the stab 90. In the on condition, the latch 56 of the tripping mechanism 80 is in a blocking relationship with respect to the latch tip 54 of cradle 44, with the operating spring 72 biasing the movable contact arm 62 in a counterclockwise direction about point 64 on cradle 44 to maintain the movable contact pad 70 in firm electrical contact with the stationary pad 76.

It will further be observed that in the on position, biasing spring 103 attempts to establish as short a distance as possible between the projection 105 on the tripping mechanism 80 and the actuating surface 102 on the first member 92 of the automatic relatching assembly whereby the planar actuating surface 100 of member 92 is necessarily so positioned as to be in the path of movement of an upstanding tab 128 (which cannot be seen in FIGURE 1) provided on the operating handle 30.

The function of this last mentioned upstanding tab 128 on the operating handle 30 may best be understood by referring to FIGURE 3 wherein the operating handle 30 has been manually moved from its on position to an off position intermediate the projections 120 and 122, and during which time the operating spring 72 has moved over point 64 on the cradle 44 to rotate the movable contact support arm 62 from its on position to its off position. The movable contact support arm moves clockwise, as viewed in FIGURES 2 and 3, until it engages mounting plate flange 150 where its motion is halted. Note that since the opening of the circuit breaker was by manual operation and not in response to the occurrence of a fault, the circuit breaker is in an elf position rather than the tripped position, with the cradle 44 still being latched by the cooperation of latch 56 and latch tip 54.

As can be most clearly seen in FIGURE 3, the operating handle 30 is maintained in the 01f position by the cooperation of actuating surfaces 100 and 102 of member 92 with the upstanding tab 128 and the cradle 44, respectively. Specifically, as the operating handle 30 is rotated by means of the knob 118 counterclockwise in FIGURE 3, the tab 128 on the operating handle 30 engages the actuating surface 100 of member 92. However, with the cradle 44 latched, further counterclockwise rotation of the member 92 of the automatic relatching assembly 12 is prevented by the engagement of the upstanding actuating surface 102 thereon with the cradle 44.

To reclose the contacts, knob 118 is moved clockwise, as viewed in FIGURE 3. When handle 30 passes over pivot 64, operating spring 72 snaps movable contact 70 into engagement with stationary contact 76.

Starting with the circuit breaker in its on condition of FIGURE 2 and turning now to FIGURE 4, it will be assumed that a time-delayed or instantaneous fault current has been detected by the tripping mechanism 80 so as to rotate latch 56 from its blocking position with respect to the latch tip 54 of cradle 44. The movable contact support arm 62 is still in the position shown in FIGURE 2. The pull exerted by spring 72 on spring retaining portion 66 pulls portion 66 toward spring retainer 74. This exerts a force on point 64 of cradle 44, thus causing the cradle, which is no longer restrained by latch 56 from clockwise rotation, to begin to rotate clockwise. Spring retainer 74, point 64 and portion 66 comprise a toggle and as spring 72 collapses and pulls up on portion 66, it causes the toggle to collapse, whereby movable contact 70 wipes over stationary contact 76. After cradle 44 has rotated a distance, the kicker projection 44a secured thereto strikes the movable contact support arm 62, and the impact separates the movable contact 70 from the stationary contact 76 and rotates movable contact support arm 62 beyond point 64.

As cradle 44 rotates, when point 64 passes to the right (as viewed in FIGURE 2) of the force line of spring 72, the toggle formed by spring retainer 74, point 64 and portion 66, collapses in the opposite direction from the previous direction of collapse of the said toggle. During this rotation of cradle 44, contact arm 62 is rotated away from stationary contact 76 with the help of kicker projection 44a.

Once spring 72 has passed beyond, or to the left as viewed in FIGURE 2, of the handle arm pivot 26, the handle 118' rotates counterclockwise. At this stage the spring 72 although not necessarily completely relaxed, is not tense sufiiciently to rotate farther past surface 100 of member 92.

Spring 42 is provided to pull handle 118 further to the left, rotating the member 92 counterclockwise so that the handle trip position is realized (FIGURE 4) and the tab 128 is in position for latching and reclosing the circuit breaker.

As can be seen in FIGURE 4, cradle 44 rotates clockwise until it abuts actuating surface 104 which stops cradle 44. Movable contact support 62 rotates until it strikes mounting plate flange 150 which prevents further opening of contact 70.

Since flange 150 halts the rotation of arm 62 when the breaker is in both the ofr' and tripped position, and since cradle 44 rotates further in the tripped condition, movable contact 70 is further from stationary contact 76 in the tripped than in the off condition.

As was noted above, with the aid of biasing spring 42, the operating handle 30 is urged through its off position in FIGURE 3 to its tripped position in FIGURE 4, it being noted that the upstanding tab 128 thereon is now free to rotate member 92 counterclockwise since the actuating surface 102 thereof isno longer restrained by the cradle 44 as it was in FIGURE 3. It is to be noted that while member 92 is being rotated counterclockwise, biasing spring 103 is put under tension whereby once the operating handle 30 has reached its tripped position and the upstanding tab 128 thereof is no longer in engagement with the actuating surface under it (this instant in time being shown in phantom at in FIGURE 4), the member 92 will be rotated clockwise back to the initial position it occupied in FIGURE 2.

To convert the breaker from the tripped condition shown in FIGURE 4 back to the on position shown in FIGURE 2, the operator merely grasps the knob 118 and rotates it (and the operating handle 30) from its position in abutment with the wall projection 120 to its other extreme position defined by the wall projection 122. In so doing, the upstanding projection 128 on the operating handle 30 engages the actuating surface 100 of member 92 once again such that the member 92 rotates clockwise in FIGURE 4 and second member 94 with the actuating surface 104 are moved toward the left in FIGURE 4, the movement of the actuating surface 104 being guided by the elongated slot 24 into contact with the cradle 44.

As this motion continues, the upstanding actuating surface 104 causes the cradle 44 to be rotated counterclockwise in FIGURE 4 until the latch tip 54 passes beneath the latch 56 (which has been urged counterclockwise in FIGURE 4 by the biasing spring 103) at which time the cradle 44 will occupy the latched position shown in FIG- URE 3.

Finally, when the operating handle 30 passes over center point 64, the operating spring 72 will snap the movable contact arm 62 counterclockwise in FIGURE 4 until it reaches the on position shown in FIGURE 2. Thus the circuit breaker has been converted from trip to on position with one continuous motion of the operating handle 30.

It should be noted that once the upstanding tab 128 of operating handle 30 is free of the actuating surface designated at 100 in FIGURE 4, the biasing spring 103 will again return the member 92 to the position shown in solid lines in FIGURE 4 (corresponding to FIGURE 2), whereby the automatic relatching mechanism will be in condition to function properly for either the next tripping operation or manual movement from the on to off positions.

There has thus been described a circuit breaker having a mechanism mounting plate assembly which is separate from the breaker casing. This eases the assembly of circuit breaker components, permits breaker casings to be molded more easily, provides a more durable mounting for movable circuit breaker components and permits circuit breakers to be made thinner.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, thisinvention is to be limited, not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which an ex- Clusive privilege or property is claimed are defined as follows:

1. In a circuit breaker comprising,

a casing for containing circuit breaker components,

said components including:

a pair of cooperating contacts;

a circuit interruption mechanism for causing separation of said cooperating contacts;

a circuit reclosing mechanism for bringing said cooperating contacts into engagement;

the improvement comprising, a mounting plate assembly for directly and indirectly mounting and positioning various of said circuit breaker components;

said mounting plate assembly comprising a plate which is separable from and mounted within said casing; said plate having means for directly and indirectly mounting and positioning said components; said components being mounted to said plate;

said plate being substantially in a plane and also being thin and flat as compared to said casing, whereby the circuit breaker will have a thin width.

2. In the circuit breaker of claim 1, the improvement further comprising said means for mounting and positioning circuit breaker components comprising apertures through said plate and tabs connected to and upraised from said plate;

said components which are directly mounted to said plate having apertures and upraised tabs for cooperation, respectively, with said tabs on and aper- 10 tures through said plate, whereby said components can be mounted to said plate. 3. In the circuit breaker of claim 2, the improvement further comprising said tabs being integral with said plate. 4. In the circuit breaker of claim 3, the improvement further comprising,

said plate being comprised of metal. 5. In the circuit breaker of claim 2, the improvement further comprising,

said components being thin and substantially flat as compared to said casing, whereby the circuit breaker will have a thin width.

References Cited UNITED STATES PATENTS BERNARD A. GILHEANY, Primary Examiner H. BROOME, Assistant Examiner US. Cl. X.R. 

